The present invention relates to a method and apparatus for providing improved thin film deposition.
There have been numerous techniques employed for depositing thin films, most of which involve the use of a substrate, which is elevated to or maintained at a relatively high temperature. This high substrate temperature has been considered necessary during the deposition of the thin film for the purpose of increasing the mobility of the atoms being deposited. However, this high temperature substrate has certain problems associated with it. For example, one disadvantage of vapor deposition upon a hot substrate is that the impurities are caused to diffuse out from the substrate and thereby affect the composition of the thin film that is being deposited. Further, the excess temperatures cause a poor definition at the junction between the film and the base substrate material.
It is known that the necessary substrate atom mobility is obtained by heating the incident ions that are to be deposited on the substrate surface rather than the substrate itself. The apparatus of the present invention takes this fact into account and permits less heating of the substrate by isolating the substrate within a separate chamber adjacent to the plasma ion source chamber. Further, the apparatus is designed to control the energy of impinging ions by appropriate biasing means coupled to the substrate material.
It is an object of the present invention, therefore, to provide an improved method and means for the deposition of thin films.
It is another object of the present invention to provide film deposition apparatus wherein the substrate can be maintained at a relatively low temperature.
A further object of this invention is to provide a method for fabricating a thin film-substrate structure wherein the film can be deposited at a high rate and in a controllable manner.
Another object of the present invention is to provide a thin film upon a base substrate wherein there has been little or no impurity diffusion from the substrate affecting the thin film deposited thereon.
Still another object of the present invention is to provide a thin film-substrate structure wherein the junction between the two substances is well defined.
Other objects of the present invention will become apparent upon reading the detailed description in conjunction with the drawings and appended claims.